Plastic flow stress, PMMA

Fig. 14 Temperature dependence of yield stress, cry, and plastic flow stress, crpf, for quenched and physically aged PMMA. Strain rate is 2 x 10-3 s-1 (From [32])...

The temperature dependence of the plastic flow stress, crpf, of PMMA is shown in Fig. 18. At high temperatures (T > 50 °C) the crpf curve is parallel to that of cry, but at lower temperatures it is gradually lower and lower, the decrease being particularly pronounced below 0 °C. 

Fig. 20 Strain rate dependence of yield stress, ay, and plastic flow stress, apf, of PMMA at the indicated temperatures (From [33])...

The temperature dependence of the plastic flow stress, higher temperatures an increase of crpf with increasing CMI content is observed, similar to that seen for oy. 

Fig. 38 Plastic flow stress of PMMA and various CMIMx copolymers versus temperature...

The temperature dependence of the yield stress and the plastic flow stress for PMMA and a large series of MGIMx copolymers [35] is shown in Fig. 44. For comparison purpose, the yield stress of PMMA and various MGIMx are presented together in Fig. 45. 

Figure 46 presents the temperature dependence of the plastic flow stress for PMMA and the various MGIMx copolymers. As it could be expected from Fig. 44, the behaviour of apf is quite similar to that of ay. 

Fig. 44 Yield stress and plastic flow stress versus temperature (strain rate of 2 x 10 3 s 1) for PMMA and various MGIMx copolymers (From [35])...

Fig. 18 Temperature dependence of yield stress and plastic flow stress of PMMA, obtained under uni-axial compression at a strain rate of 2 x 10 s ...

In the same way as for PMMA, the whole chain motions responsible for the plastic flow of CMIMx copolymers are identical to those occurring at the a transition temperature, whatever the considered temperature at which the plastic flow happens. Thus, plastic flow and the corresponding stress can be considered as a reference, as for PMMA. 

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